Improved long-term biocompatibility of coronary stents by plasma coating process Abstract Drug-eluting stents (DES) have been widely used to treat patients of cardiac disease due to their better ability to control restenosis than bare metal stents (BMS). However, a serious adverse outcome of late stent thrombosis in patients treated with DES has been reported, which leads to fatal heart attack and death even though it occurs at low rate. Thus, for safe and effective clinical use, a coronary stent needs to have better biocompatibility on its surface that will provide sufficient thrombo-resistance in addition to inhibiting cell proliferation thereby slowing down healing of tissues around the stent. Nanova, Inc. is developing a novel coating layer of high thrombo-resistance on the surface of metallic biomaterials of which coronary stents are made. An environmentally benign technology, low temperature plasma process is used to deposit an ultra-thin (nano-scale) but continuous layer of coating, sufficient to generate desired abrasion resistance and immobilize the bioactive functional groups created in the subsequent plasma surface treatment to prevent blood clots and restenosis, but thin enough to allow for stent expansion without cracking when delivered into patients. The knowledge gained in this innovative research project will also benefit research and development for improved biocompatibility in other implantable medical devices such as pacemakers, pulse generators, cardiac defibrillators and bio-sensors.